Update docs

- Be more clear as to how to enable incremental analysis
 - Fix broken links

docs/pages/pmd/userdocs/getting_started.md

@@ -36,7 +36,7 @@ Unzip it into any directory:
     [tom@hal tmp]$
 
 
-Note that the PMD binary distribution file contains both [PMD](#running-pmd-via-command-line) and [CPD](/pmd_userdocs_cpd.html).
+Note that the PMD binary distribution file contains both [PMD](#running-pmd-via-command-line) and [CPD](pmd_userdocs_cpd.html).
 
 
 ## Running PMD via command line
@@ -364,6 +364,6 @@ untouched, files with violations will be listed with full detail.
 
 Incremental analysis is enabled automatically once a location to store the cache has been defined.
 From Command Line that is done through the `-cache` argument, but support for the feature is
-available for tools integrating PMD such as [Ant](/pmd_userdocs_tools_ant.html),
-[Maven](/pmd_userdocs_tools_maven.html), and Gradle.
+available for tools integrating PMD such as [Ant](pmd_userdocs_tools_ant.html),
+[Maven](pmd_userdocs_tools_maven.html), and Gradle.
 

docs/pages/pmd/userdocs/tools/ant.md

@@ -76,7 +76,7 @@ Runs a set of static code analysis rules on some source code files and generates
       <td>cacheLocation</td>
       <td>
         The location of the analysis cache file to be used.
-        The cache can greatly improve analysis time without loosing analysis quality.
+        Setting this property enables Incremental Analysis, which can greatly improve analysis time without loosing analysis quality.
         <b>It's use is strongly recommended.</b>
       </td>
       <td>No</td>

docs/pages/pmd/userdocs/tools/maven.md

@@ -112,6 +112,20 @@ writing a ruleset can be found [here](pmd_userdocs_understanding_rulesets.html).
 Note that if you include other rulesets in your own rulesets, you have to be sure that the plugin
 will be able to resolve those other ruleset references.
 
+#### Enabling Incremental Analysis
+
+When using the Maven PMD plugin 3.8 or later along with PMD 5.6.0 or later, you can enable incremental analysis to
+speed up PMD's execution while retaining the quality of the analysis. You can additionally customize where the cache is stored::
+
+    <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-pmd-plugin</artifactId>
+        <configuration>
+            <analysisCache>true</analysisCache> <!-- enable incremental analysis -->
+            <analysisCacheLocation>${project.build.directory}/pmd/pmd.cache</analysisCacheLocation> <!-- Optional: points to this location by default -->
+        </configuration>
+    </plugin>
+
 #### Other configurations
 
 The Maven PMD plugin allows you to configure CPD, targetJDK, and the use of XRef to link